Hi Cookj ! I was having a look to this RITTER electronic systems, and they sell output transformers at very good prices, but i dont know the quality of this transfos ! Did you ever tested one of those ? Can you tell me something about the quality ? Thanks

after looking at a few other makes of OP Tx...edcor has better low frequency..I'll use Hammond mains..(Keep the weight down)

Then whats in the box ?(rectifier) 5y3...It can be used horizontal if the pins 2/4 are vertical...I'll try and get it upright...
NB its an all valves/Tx's mounted in the box build I hope..

A couple of Mullard EF86 (Paint missing from a quick wash) should last about 35seconds to 20 years dependant upon power up.. Sylvania 5Y3..about the same.. (Then again the 5Y3 is new so maybe it will last a bit longer)